Field of Technology
The present disclosure relates generally to track inspection, and, more specifically, to an automated track inspection system operable to autonomously provide geometry measurement inspection methods as well as autonomously navigate track junctions.
Description of Prior Art
The railroad track inspection market generally includes two major geometry measurement inspection methods. The methods include geometry measurements when the track is in an unloaded or loaded state.
Unloaded measurements refer to geometry measurements that are taken when the rails are not under the load of a locomotive or rail car. Unloaded measurements do not account for the weight of the locomotive or rail cars that physically spread the railroad gauge, cause rolling of the rails, and other geometric phenomenon when a load is applied. Loaded geometry measurements generally are taken when a locomotive, rail car, or simulated load is on the rails.
One way the railroad track inspection industry has attempted to increase the frequency of measuring loaded gauge is through the deployment of contact or optical sensors installed on existing rail cars or locomotives. However, because rail cars and locomotives typically are stored in rail yards for days at a time to load and unload goods, the associated sensors may be unavailable to measure gauge on a daily basis unless substantially every rail car and locomotive is equipped with such gauge measurement sensors.
When a locomotive or rail car is not available to generate a loaded state, load may be applied using various methods to include (1) a Portable Track Loading Fixture (PTLF), (2) a heavily weighted specialized track geometry measurement car, or (3) a split-axle loading mechanism to replicate the load. Loaded measurements facilitate identification or issues with the track that may not be identified through an unloaded measurement. Replicating the load of a train, however, is a costly effort that typically requires specialized equipment to efficiently collect these measurements in a short time period to minimize impact to revenue generating train operations.
The PTLF is a manually operated device that leverages a hydraulic piston to apply a lateral load replicating the lateral loads of a locomotive or rail car on the track. As a manual device, the PTLF is designed to conduct point measurements since it would be cost and time prohibitive to attempt manual measurement of loaded track geometry across an entire network of railroad infrastructure using a PTLF device on a regular basis. The PTLF device, however, requires a human to align the device, ensure the device is contacting the appropriate points on the rail, and to ensure that the device is not obstructed by other railroad track hardware such as spikes, spring clips, frogs, joint bars, and other equipment that could physically impede the proper use of the PTLF device.
Specialized track geometry cars replicate the load of a train through the use of ballast to simulate the weight of a train, or via a hydraulic split-axle mechanism that applies a horizontal and vertical load on the rails of a track. These specialized track geometry cars are relatively expensive to operate because a human is required to drive the vehicle along the rails, while an additional individual monitors the geometry measurements. As humans are physically present in the vehicle, rail operations are separated from train operations by a greater distance or time to ensure the safety of the human. These specialized vehicles may impose scheduling constraints on revenue train operations that may result in infrequent deployment. Additionally, split-axle systems have a tendency to result in a derailments due to the large lateral forces applied at the head of the rail causing delays in both inspection processes as well as revenue operations.
An alternative to specialized track geometry cars utilizes optical geometric measurement sensors, similar to those on specialized track geometry cars, on “revenue generating” trains. In the simplest of terms, a “revenue” rail car or locomotive contains optical geometric measurement sensors that collect loaded geometry measurements via the load of the train itself. The train is thereby generating revenue as it is also measuring geometry. However, because rail cars travel across various rail networks and spend a portion of time in rail yards loading and unloading goods, the availability of the rail car and associated sensors are restricted to the schedule of that rail car. In order to ensure frequent day-to-day inspection, the railroad would require widespread deployment of these sensors on a majority of the rail cars owned by the railroad, as well as the rail cars that are owned by other railroads that share track.
The manual operation of the PTLF device, the limited frequency of a specialized track geometry vehicle, and the otherwise extensive deployment of geometry sensors on revenue trains may impede railroad operators from conducting loaded gauge measurements on a desired frequent day-to-day basis.